1) Linguistics thesauri

Examples: Exercise: Search for the words: football, spring, although. Which system has a better interface? Which search options are available? What happens if you misspell a word? What are the broader terms for "football"? Can you find antonyms of "spring"?

2) Information retrieval thesauri

Establish formal relationships among terms, such as Examples: Exercise: Find documents on informatics and thesaurus. In what way does the thesaurus on the right side help with the search? Can you use it to broaden or narrow a search?

3) Lexical databases: WordNet

Establishes semantic relations among words: Examples: Exercises: a) Search for spring, football, although, informatics in the four databases.
b) Try the different search options in WordNet. Can you find meronyms and antonyms for spring? How many senses has football?
c) In the Plumb Design Thesaurus, can you establish a connection between spring and fall?
d) Try the different search options in Lexical FreeNet. Can you find a connection between spring and fall in Lexical FreeNet? Try the search for famous people in Lexical FreeNet.

4) Formal Ontologies: CYC and Ontolingua

Examples: Exercises: a) In CYC: have a look at Food and Clothing. What kinds of food are mentioned? How is food prepared and consumed? What are the other main concepts related to food? What types of clothes does CYC know of? What are the main activities related to clothes?
b) In Ontolingua: click on "documents". Have a look at the class hierarchy, the relations and function. (Ignore the incomprehensible stuff at the top of the page.)